When working in the Basic Panel in ACR, I would like to selectively review changes of only one slider at a time. For instance, I have have adjusted exposure and now have also adjusted blacks, how can I preview the change in Blacks while the adjusted Exposure is still in effect? If I toggle the Preview button on and off, I see all the changes cumulatively. I have tried using the command key, shift, key and option key however, that doesn't seem to work.